Cisco 400-007 Exam With Confidence Using Practice Dumps

OSPF throttling timers control the pacing and frequency of SPF calculations and LSA generation. They help strike a balance between fast convergence and control-plane stability. The key timers include:

LSA generation throttling (min/max interval between LSA originations)

SPF calculation throttling (delays between consecutive SPF runs)

By tuning these timers, network designers can:

Prevent CPU overload caused by rapid or repeated LSA updates due to flapping links

Smooth out instability while still enabling responsive convergence

This approach aligns with CCDE v3.1 under “Protocol Design Implications” for optimizing IGP behavior in large, dynamic topologies.

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SDN controller — Maintains a complete view of everything that is happening in the network; Manifested as either a physical or virtual component

Southbound interface — Communicates with network devices to program the data plane; Provides access to the network to configure or to retrieve information from it

Northbound interface — Exposes access to the controller; Characterized as a software interface

Ingress filtering (also known as uRPF or source address verification) prevents packets with spoofed source addresses from entering the network. By validating that incoming packets have legitimate source addresses (based on routing tables or prefix lists), ingress filtering directly blocks many spoofed DDoS attacks, which often rely on forged source IP addresses.

This principle is foundational in network security design per CCDE v3.1:

Stops source-spoofed attacks before they enter.

Protects critical infrastructure from volumetric and reflection/amplification attacks.

Forms part of secure edge design best practices.

Why other options are incorrect:

A: DSCP remarking relates to traffic classification, not spoof prevention.

C: Bogon classification isn ' t the main function of ingress filtering.

D: RFC 1918 filtering is a special policy but not the core function of ingress filtering.

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